Pull tabs to be used for sliders of slide fasteners comprising a metal member and a grip integrally molded of synthetic resin such as rubber with the metal member are known and have been designed for the effect of quality, esthetic appeal and/or comfortable touch, as disclosed in Japanese patent Application Laid-Open No. 6-189810. Additionally, it is a popular practice to attach a metal pull tab member to the slider body of a slide fastener in advance, insert the metal pull tab member into the metal mold of an injection molding machine and coat the metal member with synthetic resin while integrally forming a grip of a desired profile. At present, however, the operation of inserting the metal pill tab member attached to the slider body into the injection molding machine and placing it in position is exclusively performed by hand.
While pull tabs of such type can expect the effect of quality, esthetic appeal and/or comfortable touch and hence have been popularly used, they are costly and hence cannot significantly enlarge the market any further because they are manually prepared with poor productivity. Therefore, there is a strong need for technological development that can improve the productivity and reduce the cost of manufacturing such pull tabs.
In view of the above identified need, it is therefore the object of the present invention to provide an automatic pull tab insertion unit of an insert molding machine that can automatically insert a plurality of metal pull tab members fitted to respective sliders of slide fasteners into the insert molding machine in order to form a synthetic resin grip integral with each of the metal pull tab members.